|Kimbeng, C - LSU, BATON ROUGE, LA|
|Legendre, B - LSU, BATON ROUGE, LA|
Submitted to: Sugar Cane International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2006
Publication Date: April 28, 2006
Citation: Kimbeng, C.A., White, W.H., Miller, J.D., Legendre, B.L. 2006. Sugarcane resistance to the sugarcane borer: response to infestation among progeny derived from resistant and susceptible parents. Sugar Cane International. 24(3):14-21. Interpretive Summary: In Louisiana, the deployment of sugarcane borer-resistant varieties is a central part of the integrated pest management approach to minimizing injury from borer infestation. However, under the current strategy for developing varieties in Louisiana, often little attention is paid to insect resistance and new varieties released to growers are just as likely to be susceptible to the borer as resistant; a practice that places too much emphasis on the use of insecticides to control the insect. In this study, borer resistance was evaluated in a set of crosses obtained from the breeding program at our laboratory and the data analyzed relative to the resistance rating of parents involved in the cross. Our aim was to demonstrate, in a practical way, the potential benefits of parental selection as a means to incorporate sugarcane borer resistance into commercial varieties. The study was conducted in the field over a two-year period in replicated field plots and involved 13 crosses of varying combinations of borer resistant and susceptible parents. Native borer infestations were augmented through intercropping corn and inoculating the corn with laboratory reared insects. Our results indicate that sugarcane borer resistance could be reliably increased by diligently selecting and crossing among at least one resistant parent followed by standard selection based on yield performance. These results are of major importance to plant breeders as it provides a passive means to increase borer resistance in a breeding program without encumbering that program with an additional selection trait. For each selection trait added to the breeding program, the number of plants required in the initial stage of selection must be increased with an accompanying increase in costs and land requirements.
Technical Abstract: The sugarcane borer (SCB), Diatraea saccharalis (F.), is the most important insect pest of sugarcane (Saccharum spp.) in Louisiana. The deployment of SCB-resistant varieties is an integral part of the integrated pest management approach to minimizing injury from SCB infestation. Our objective was to evaluate the response to infestation among sugarcane progeny derived from SCB resistant (R) and susceptible (S) parents. SCB resistance was measured, as percent borer-damaged internodes, among progeny from 13 bi-parental crosses in the plant-cane (1998) and first-ratoon (1999) crop years and the Best Linear Unbiased Prediction (BLUP) effect for each cross was estimated. Significant BLUP estimates (i.e., BLUP < 0 at the 0.05 level) were found for the same set of crosses in both crop years. These crosses had at least one resistant parent (R x S and IR x R) whereas none of the S x S crosses could be categorized as resistant. Results as to whether the resistant parent should be used as a male or female were inconsistent probably reflecting the complex contribution and interaction of several mechanisms that govern resistance of sugarcane to the SCB. Progeny mean BLUP estimates in the two crop years were highly correlated despite the large disparity in the level of borer infestation in the 2 crop years (Mean: 20.4% in 1998 and 6.4% in 1999). In both crop years, the genetic variation and genetic coefficient of variation among crosses were smaller compared with those within crosses. These results indicate that, population-wide SCB resistance could be reliably increased by diligently selecting and crossing among the most resistant parents and then focusing selection on progeny within those crosses.